Species group report card




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Analysis of pressures

On the basis of current information pressures have been analysed for the four cetacean species discussed in this report card. A summary of the pressure analysis for cetaceans is provided in Table 2. Only those pressures identified as of concern or of potential concern are discussed in further detail below; no pressures have been assessed as of concern for these four species in the South-west Marine Region. An explanation of the pressure analysis process, including the definition of substantial impact used in this analysis is provided in Part 3 and Section S1.1 in Schedule 1 of the plan.



Table 2: Outputs of the cetacean species pressure analysis for the South-west Marine Region

Note: To maintain uniformity among all bioregions, this table has been added subsequently to the review by independent experts.



Pressure

Source

Species

Blue whale

Humpback whale

Southern right whale

Sperm whale

Sea level rise

Climate change













Changes in sea temperature

Climate change













Changes in oceanography

Climate change













Ocean acidification

Climate change













Chemical pollution/contaminants
















Nutrient pollution
















Changes in turbidity
















Marine debris

Aquaculture infrastructure

Fishing boats

Land-based activities

Oil rigs

Renewable energy infrastructure

Shipping

Urban development

Vessels (other)


















Legend




of concern




of potential concern




of less or no concern


Table 2: Outputs of the cetacean species pressure analysis for the South-west Marine Region

Note: To maintain uniformity among all bioregions, this table has been added subsequently to the review by independent experts.



Pressure

Source

Species

Blue whale

Humpback whale

Southern right whale

Sperm whale

Noise pollution

Aquaculture infrastructure

Defence/surveillance activities

Onshore and offshore construction

Onshore and offshore


mining operations

Renewable energy infrastructure

Seismic exploration

Shipping

Urban development

Vessels (other)















Light pollution















Physical habitat modification

Dredging (and/or dredge spoil)

Onshore construction

Urban/coastal development














Human presence at sensitive sites















Nuisance species
















Extraction of living resources
















Bycatch

Commercial fishing













Oil pollution

Oil rigs

Onshore and offshore mining operations

Shipping

Vessels (other)















Collision with vessels

Fishing

Shipping


















Legend




of concern




of potential concern




of less or no concern


Table 2: Outputs of the cetacean species pressure analysis for the South-west Marine Region

Note: To maintain uniformity among all bioregions, this table has been added subsequently to the review by independent experts.



Pressure

Source

Species

Blue whale

Humpback whale

Southern right whale

Sperm whale

Collision/entanglement with infrastructure

Aquaculture infrastructure

Renewable energy infrastructure















Disease
















Invasive species



















Legend




of concern




of potential concern




of less or no concern


Changes in sea temperature–climate change

Changes in sea temperature have been assessed as of potential concern to blue whales through changes in distribution associated with the availability of suitable habitat. Sea temperatures have warmed by 0.7 °C between 1910–1929 and 1989–2008, and current projections estimate that ocean temperatures will be 1 °C warmer by 2030 (Lough 2009). South-west Western Australia is considered one of three hotspots in the Indian Ocean where rising temperature trends exceed the Indian Ocean basin average (Feng, Weller & Hill 2009). Changes in sea temperature are likely to result in changes to zooplankton communities with implications for dependent species, such as the blue whale (Richardson, McKinnon & Swadling 2009). The blue whale is the only one of the baleen whales assessed that feeds in the region.



Changes in oceanography–climate change

Changes in oceanography have been assessed as of potential concern to blue, southern right, humpback and sperm whales, through impacts on distribution associated with the availability of suitable habitat and prey (e.g. breeding and feeding). The Leeuwin Current’s southward flow has weakened slightly since 1970 (Feng, Weller & Hill 2009). The recovery plans 2005–10 for Australia’s threatened whales: humpback, southern right, blue, fin and sei indicate that some habitat may become unsuitable for feeding or calving (DEH 2005a, 2005b, 2005c) due to changes in the distribution of prey. For example, the selection of calving sites may be influenced by factors such as ocean currents and water temperature and, given the possible changes in oceanography, existing calving sites may become smaller in size or rendered unsuitable in the future (DEH 2005a, 2005b, 2005c).



Ocean acidification–climate change

Driven by increasing levels of atmospheric carbon dioxide and subsequent chemical changes in the ocean, acidification is already underway and detectible. Since pre-industrial times, acidification has lowered ocean pH by 0.1 units (Howard et al. 2009). Furthermore, climate models predict this trend will continue, with a further 0.2–0.3 unit decline by 2100 (Howard et al. 2009).

Ocean acidification has been assessed as of potential concern to blue, southern right, humpback and sperm whales through impacts on prey availability. There are no observed impacts of climate change on zooplankton in Australian waters. However, based on knowledge of impacts elsewhere, Australia is likely to start losing calcifying zooplankton from its southern waters (Richardson, McKinnon & Swadling 2009). Recent research on the effects of ocean acidification on Antarctic krill has found that increased levels of carbon dioxide kill their embryos (Kawaguchi et al. 2010). The Southern Ocean is expected to be severely affected by ocean acidification, with cold water readily taking up carbon dioxide. Southern Ocean carbon dioxide levels at depths could rise to 1 400 parts per million by the year 2100 (Kawaguchi et al. 2010). As Antarctic krill is the key species of the Southern Ocean ecosystem, effects of such increases in carbon dioxide would be widespread, including affecting baleen whales that visit Australian waters.

Marine debris

Marine debris has been assessed as of potential concern for southern right, blue, humpback and sperm whales. Plastic garbage washed or blown from land into the sea, fishing gear abandoned by recreational and commercial fishers, and solid non-biodegradable floating materials (such as plastics) disposed of by ships at sea are all considered to be harmful marine debris. Plastic bags are known to contribute to the death of cetaceans. In addition, whales can become entangled in derelict fishing gear such as lost nets and pots. The impact of entanglement in marine debris is difficult to measure, because animals may die at sea and not be detected.

Marine debris is listed as a key threatening process under the EPBC Act because of the threat it poses to all marine life, especially to species listed as threatened under the EPBC Act. The Australian Government has developed a threat abatement plan that provides a coordinated national approach to prevent and mitigate the effects of harmful marine debris on vertebrate marine life (DEWHA 2009). This threat abatement plan lists a number of cetaceans, including southern right, blue and humpback whales as being adversely affected by ingestion of or entanglement in harmful marine debris (DEWHA 2009). Whale recovery plans for humpback, southern right, blue, fin and sei whales (DEH 2005a, 2005b, 2005c) identify entanglement in derelict fishing gear and ingestion of plastics at sea as pressures.

Based on recorded strandings and sightings of the four whale species, the ingestion of marine debris causes deaths most frequently in sperm whales, while entanglement is recorded most often in humpback whales (Ceccarelli 2009). There is limited information about the distribution and quantity of marine debris in the region. Deaths of southern right whales in the region involving entanglement, most commonly in discarded fishing gear, appear to be increasing relative to the number of carcasses reported (Kemper et al. 2008).



Noise pollution

Noise pollution from a wide range of activities including shipping, seismic survey, sonar, industrial activities and naval exercises has been assessed as of potential concern to blue, southern right, humpback and sperm whales. There is growing concern that man-made noise impacts marine life, particularly cetaceans, because it may result in physical and/or behavioural effects on these species (DEWHA 2008a). All sources of man-made noise in the region—shipping, marine infrastructure construction and operation, and seismic surveys—are predicted to increase (Clifton et al. 2007). Defence naval exercises also occur in the region. Guidelines under the EPBC Act are in place to mitigate the effect of noise generated by seismic surveys on whales; similarly, the Royal Australian Navy implements operational procedures to minimise environmental impacts.

Anthropogenic noise may affect cetaceans by masking sounds that are vital for their essential activities and behaviours, including navigation, identifying the location of prey and predators, announcing location and territory, establishing dominance, attracting mates, and maintaining group cohesion and social interactions (Richardson et al. 1995; Simmonds, Dolman & Weilgart 2004). Noise pollution can also modify behaviour through attraction and avoidance to sound. Close exposure to noise can cause temporary or permanent physical injury.

Oil and gas exploration and other geophysical surveys involve the use of seismic ‘air-guns’, which generate a rapid release of air under high pressure to obtain a geologic profile of the sea floor and substrate. This activity creates the noise signal that can have physical and behavioural effects on some species of cetaceans (DEWHA 2008a). For example, it may cause baleen whales (e.g. humpback and blue whales) and large toothed whales (e.g. sperm whales) to detour away from migration routes or from feeding or breeding areas. Extremely close encounters may damage their ears. The EPBC Act Policy Statement 2.1 provides guidance on the implications of seismic surveys for cetaceans (DEWHA 2008b).

The Western Australian Exercise Area (WAXA) extends over the Perth Canyon, which is known to be an important seasonal feeding aggregation area for pygmy blue whales. The Department of Defence conducts a range of activities that create noise in the WAXA, such as the use of active sonar to locate targets and the use of live ammunition. The Department of Defence operates in accordance with an environmental management plan, supported by planning guides and procedural tools, aimed at mitigating impacts on the marine environment and marine species.

Shipping is a major activity in South-west Marine Region, transporting goods through the region and to and from ports in the region. Shipping traffic in the region is predicted to increase (Clifton et al. 2007), particularly in line with new port improvements and developments earmarked for Albany and Oakajee (near Geraldton). In other parts of the world where the issue has been investigated, the increased traffic of faster and larger ships has led to rising concerns over associated effects on cetaceans (e.g. Hatch et al. 2007).



Physical habitat modification

Habitat modification has been assessed as being of potential concern to southern right whales. Inshore habitat degradation is considered a threat to the recovery of southern right whales because this species uses inshore areas for calving, some of which are close to populated centres (DEH 2005a). Swimming further to avoid degraded habitat might compromise reproductive success. This pressure is greater for the small proportion of southern right whales that calve east of Adelaide, because of the higher population density and use of coastal areas along the south-east of Australia. However, coastal and inshore habitat degradation is also of potential concern in south-western Australia, due to the anticipated expansion of coastal infrastructure and urban development (Clifton et al. 2007).



Bycatch

Bycatch has been assessed as being of potential concern to humpback, southern right and sperm whales. Southern right whales may be particularly vulnerable to entanglement in the ropes and lines associated with trapping crustaceans in coastal waters (Kemper 2008). The number of southern right whale mortalities involving entanglement appears to be increasing relative to the number of carcases reported (Kemper et al. 2008). The likelihood of entanglement may increase as the southern right whale population recovers. There have also been reports of sperm and humpback whales being entangled in fishing gear (Kemper et al. 2008), and interactions are likely to increase as the populations of these species recover.



Oil pollution

Australia has a strong system for regulating industry activity that is the potential source of oil spills and this system has been strengthened further in response to the Montara oil spill. While oil spills are unpredictable events and their likelihood is low based on past experience, their consequences, especially for threatened species at important areas, could be severe. Chemicals used to disperse oil pollution can themselves be toxic to marine life (AMSA 2011).

Oil pollution has been assessed as of potential concern to blue, southern right, humpback and sperm whales. The intensity and distribution of activities implicated in oil spills – such as oil production and transport – are likely to increase in the region. Baleen whales are particularly vulnerable to oil pollution as the oil is likely to stick to the baleen plates while whales filter-feed on plankton and krill near oil slicks (AMSA 2010). Where an oil spill coincides with calving and nursing events, it may affect breeding success (DEH 2005a, 2005b, 2005c). Southern right whales are listed as endangered and the effects of an oil spill, particularly in calving areas, could interfere with the recovery of the species.

Collision with vessels

Collision with vessels has been assessed as of potential concern for blue and southern right whales, with reference to locations where their biologically important areas overlap with shipping lanes). Southern right whales are particularly vulnerable to vessel collision because they spend about half of each year in coastal waters where human activities are often intense. Fatal strikes by ships have been recorded in the region, involving southern right and blue whales (Kemper et al. 2008; Australian Government 2007). The relative importance of this source of mortality is unknown, but it is not likely to impact the species at the population level; however, it is possible that a number of events are undetected, especially those that occur well offshore (Kemper 2008). A review of ship strike records around the world (but not including Australia) found that, in some areas and for small populations, ship strikes are a significant source of mortality (Laist et al. 2001). Shipping traffic, particularly of large vessels, is expected to increase (Clifton et al. 2007), and shipping routes in the region overlap with some biologically important areas for these species.



Collision or entanglement with infrastructure

Collision or entanglement with infrastructure has been assessed as of potential concern to southern right whales as the nature of the interaction can be fatal. The species is particularly susceptible because it spends about half of each year in coastal waters, where human activities are more intense (Kemper et al. 2008). Interactions between southern right whales and fish farm cages have been reported (Kemper et al. 2003; Kemper 2008). The relative importance of this source of mortality is not known, but it is not likely to be significant at present; however, marine aquaculture and renewable energy infrastructure in the region are predicted to increase. Open-ocean aquaculture and commercial-scale offshore renewable energy technologies are emerging industries, and entail uncertainties regarding their potential scale, technology and impacts (Dolman, Green & Simmonds 2007).


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